Bleed cooling system

[badhabt]

So I'm going to bleed the cooling system today. I've got all the info I need to get it done. Nonetheless, any extra advice or tips are welcome.

Some people, in my research, say to drain the the coolant first. Others don't.

So what is it? Can I bleed the system without draining? Logically speaking, the air travels up and out whether the system is drained or not...right?

Thanks

 

[cztheman64]

what are you trying to accomplish?

 

[badhabt]

There is air trapped in the cooling system.

 

[DC runner]

Pretty simple, actually. Drain the system or don't, no matter. Then, whether you buy 50/50 mixed or concentrate that you add water; you will fill the radiator. Turn the truck on, turn the heat on full blast, to open the heater core.

Eventually, in about 2 minutes or so, the t-stat will open and the water pump will start pushing water around.

You will now be "burping" it. As air pockets are moved out, the water(coolant) will drop. FIll. Keep doing this. You just kinda stand there for 15 minutes, while the truck is on with either a hose or the bottle of coolant. You will be seeing air burping out, water level will drop. Fill up radiator. Watch.

Eventually the burping will stop and the water/coolant will just be smoothly flowing by. Wait for another couple of minutes, just to be sure. And.. bam. DONE.

 

[badhabt]

So I did it for 15 minutes, then decided to let it bleed for an other 15. I did see air bubbles coming out of the radiator. I did not need to refill with coolant because it was full, and it stayed full through the process. The spill over reservoir was full too. It did work, but not entirely.

Its not as bad, but it's not gone. I can still hear a little air flushing through system. So I tried again. I parked it on a hill, with the front end pointing up. Still didn't get the remaining air.

I might have to go ahead and drain the fluid, and do a more thorough job of it.

Any thoughts?

 

[DC runner]

Nah. You are prob good. You had the heat on? People forget that. All that plumbing can hold air. Dont drain. No need. Draining will introduce more air. Might be a little , but it can work its way out through the pressure relief cap. It isnt an airtight seal. If your temp is staying steady, and in themiddleish of the dial...you are good.

You hear the air? How? Engines are loud...what are you hearing? You probably onlyhad a few pockets...

 

[badhabt]

Yeah I turned on both heaters front and back.

It does not overheat. It's never been over the mid mark. In fact I've never even seen it get to the middle.

 

[fourwd1]

I might have to go ahead and drain the fluid, and do a more thorough job of it.

Any thoughts?

That's not a solution, just a chance to get more air in the system.
Keep burping it.

 

[badhabt]

I just took lightening Mqueen (named by my daughter) on a fishing expedition, around 300 ish miles round trip. Everything worked great, truck runs great. I heard fluid rushing through the entire trip. It's kind of a strange experience to be driving through a rain storm while hearing water rush/flush behind your dash.

You hear the air? How? Engines are loud...what are you hearing?

I hear fluids flushing/rushing through the system when I accelerate. Not sure where the sound is coming from; it seems to be behind the dash..like the heating system maybe?

The amount of noise I hear tells me there is loads of air getting in. Thats just my guess.

Coolant is not disappearing. The engine is not overheating. Heater does not leak coolant, or water.

I'll burp it again.

 

[ToyoTech]

there was a recall or tsb for this sloshing should. there was an updated heat core hose that was suppose to help let that pocket of air bleed out . the problem i think was the hose sat higher than where the filler neck was. if replacing the hose isnt an option.

the trick i have heard was to jack the front end up as high as you can.
open radiator cap
set air temp to heat
dont turn heater on
start the truck
let it run till operating temp
while topping off the coolant
once it has been warmed up and ran a few mins after that
install cap
turn truck off
top of reservoir tank a little past full
lower front end up and let it cool down.
done

note use toyota coolant if you dont want to increase your chances of having the HG failure. green coolant uses a different chemical which i have heard sound be used in toyotas or hondas for that matter.

 

[badhabt]

set air temp to heat
dont turn heater on

Uhhh, I "set air temp to heat", but DID turn on heater.

I'll give it another go, and WON'T turn on heater.

Also, I did call Toyota, gave them my vin, and was told there were "no recalls" on my truck.

Thanks

 

[DC runner]

Yea. The part about heat fan on is more a to make sure the heat core tubing open.

I know on the 4runner, the valve to allow coolant to move through the heating plumbing is physically connected to the temp level. On some vehicles that are all fancy electronic controlled, it isn't until you turn a fan on that it opens the port.

So. You don't actually need a fan on, what you are shooting for is making sure the valve is open so water is moving through.


Was unaware of the TSB. You may have a bit of air that never wants to move out. If it is isolated to the heater core, and your vehicle isn't overheating; honestly, don't sweat too much over it.

Toyotech seems to have a good understanding, and his explanation makes sense. Any time you have a bit of plumbing set higher than your bleed point (radiator cap) this will cause all kinds of annoyance and is likely a design slip up. If toyota works like other places, different areas are designed by different teams and I bet they don't talk much.


Anyway. My point is, the high point is NOT an integral component. A small air pocket will not impact, much, temperature ability. I bet your heat still works nice? Correct? So, just to at least let you know you won't blow your engine up: You sound totally fine!

 

[badhabt]

Yeah, heater works great!

I'm not sweatin it. Just wanted to see if I could cancel it out...it is kinda annoying. I can live with it though.

I read once, a guy ended up having a blown head gasket, and the only symptom was air in the cooling system. Didn't overheat, trucked worked great, but still had a blown head gasket. That said, I was hoping to cancel that possibility out by removing the air, and seeing if it would come back. However, I know now getting rid of trapped air won't give me any kind of diagnosis.

It's clear that there is more than one possibility when it comes to air getting in the system--bad plumbing, engineering, bad HG.

Thanks for all help.

 

[ToyoTech]

the reason i said not to turn the heater on is because it just makes it longer for the engine to warm up

 

[Radial GT]

Best purchase ever!

Amazon.com: Lisle 24610 Spill-Free Funnel: Automotive

Buy one of these. Mess free, and WILL get all of your air out of your system. I had to buy one for my RX7 because that thing would douch coolant everywhere when you were trying to bleed it out.


GL!

 

[Hyde802]

I put a T valve up by the firewall on the highest point of the cooling system (3vze) and just open the cap to bleed it. It was cheap and no mess. Ill get a pic this weekend.

And welcome to T4R!

 

[badhabt]

I put a T valve up by the firewall on the highest point of the cooling system (3vze) and just open the cap to bleed it. It was cheap and no mess. Ill get a pic this weekend.

And welcome to T4R!

Sounds like a great idea...cant wait to see it.

Thanks

 

[Hyde802]

the reason i said not to turn the heater on is because it just makes it longer for the engine to warm up

You need to turn the heater on so that ALL the coolant circulates.

Heres a pic of the T valve I put in. Fill right through it if needed.

 

[badhabt]

Thanks for the pic Hyde...

 

[ToyoTech]

You need to turn the heater on so that ALL the coolant circulates.

you just need to set it all the way to hot. you dont need the blower motor on. once you set it to heat, it already lets coolant flow into the heater core. turning it on only turns the blower motor on.